Magnetic feed for grinding machine



Oct. 2, 1956 J. D. BUSEY 2,764,850

MAGNETIC FEED FOR GRINDING MACHINE Filed Aug. 17, 1955 IN V EN TOR. James DaiZas .Bu .5 9y

PARKER 2 CARTER ATTORNEYS 2,764,850 MAGNETKI FEED FOR GRINDING MACHINE James Dallas Busey, South Beloit, 111., assignor to Besly- Welles Corporation, Beloit, Ill., a corporation of Illinois Application August 17, 1955, Serial No. 529,053 3 Claims. (Cl. 51-112) This invention relates to improvements in mechanisms for feeding work pieces, such as piston rings, to grinding machines and more particularly to feeding mechanisms of the magnetic type wherein the work pieces are picked up on a magnetic disc and pushed through the grinding zone in a continuous procession.

Magnetic feeding mechanisms for piston rings and the like have heretofore been employed with a feeding disc of either permanent or an electro-magnet. With both types of disc it has been noted that the work pieces tend to retain residual magnetism after they have been removed from the magnetic disc, for passage through the grinding zone of the grinding machine. It has therefore been customary to de-magnetize the work pieces after they have been ground, so as to eliminate any tendency to adhere to each other or to other metallic objects when they are put into use. It has not been fully appreciated, however, that the residual magnetism in relatively thin and flat ringlike work pieces such as piston rings can be sufficient to cause warpage or deformation of the individual rings to such an extent as to materially reduce the uniformity and precision in the finished rings.

One of the principal objects of the invention is to provide an improved form of feeding mechanism of the character described, and method of operating the same, wherein the metal work pieces are fully de-magnetized after they have left the magnetic disc, but are guided or pushed through the grinding zone, so as to result in greater uniformity and precision in the final product.

Other objects and advantages of the invention will appear from time to time as the following description proceeds.

The invention may best be understood by referring to the accompanying drawing in which:

Fig. 1 is a fragmentary end view of a grinding machine with a magnetic feed attachment made in accordance with my invention.

Fig. 2 is a fragmentary plan view of the machine and attachment shown in Fig. 1.

Referring now to the details of the embodiment of the invention shown in the drawings, Figure 1 shows a portion of the grinding machine of a conventional type used for grinding opposite sides of piston rings as the latter are passed between two opposed grinding wheels 11, 11 on power driven spindles (not shown). The rings 13 are guided in succession through the grinding zone between upper and lower guide bars 14 and 15, extending in vertically spaced relation to each other from a feeding mechanism indicated generally at 16. This feeding mechanism includes a rotating magnetic disc 17 which may be either of a permanent magnetic type or of an electromagnetic type. In either case, the disc is arranged so that its face rotates in a plane in line with the upper and lower guide bars 14 and 15. The outer ends of said guide bars extend partially across the face of said disc near one edge of the latter, in position to pick off successive rings, which are fed to the face of the disc from before theytates Patent a magazine feeder indicated generally at 16. A semicircular guide ring 18 aids in directing the rings between said guide bars.

In the illustrative form shown, the magazine feeder 16 is of a conventional vibrator type including a V-shaped trough 19 arranged to deliver work pieces to the magnetic disc at a point circumferentially spaced from the pick-off ends of the guide bars 14 and 15. The construction and operation of the feeding mechanism and its relation to the magnetic disc is well known in the art and need not be further described herein as it forms no essential part of the present invention.

Means cooperating with the upper and lower guide bars 14 and 15 are provided to form the guideway for the work pieces from the pick-off point on the magnetic disk to the point where the work pieces enter the grinding zone between the grinding wheels 11, 11. In the form shown herein, an intermediate guide bar 20 is disposed between and along the upper and lower guide bars 14 and 15 and in spaced relation to the face of the magnetic disc 17, to engage the outer sides of the successive work pieces as they move along the said guideway.

The inner side of the workpiece guideway herein consists of a continuous guide plate 21 which has its outer end 22 flush with, and curved to fit the adjacent periphery of the magnetic disc. The inner end of said plate terminates substantially flush with the grinding wheels 11, 11 so that the successive rings are passed directly between the opposed faces of the two grinding wheels 11, 11.

Referring now more particularly to the novel feature of my invention, I provide a demagnetizing unit indicated generally at 23, disposed immediately adjacent the guide way, and between the magnetic disc 17 and the grinding wheels 11, 11. In the form shown herein, the demagnetizing unit 23 consists of a casing 24 mounted flatwise against the guide plate 21 and having a coil 25 mounted therein in position to demagnetize the work pieces as they pass along the guideway, before reaching the grinding wheels 11, 11.

In the preferred form of demagnetizing unit shown herein, the demagnetizing coil 25 surrounds the center leg of a generally E-shaped laminated core 26, with the open ends of the core facing the guideway along which the work pieces are passed, close to the guide plate 21. Said guide plate is preferably made of a suitable noninductive or insulating material such as Bakelite, to reduce the effects of induction heating which otherwise would tend to produce excessive heating due to the operation of the demagnetizing unit.

The use and operation is as follows: The work pieces, herein consisting of piston rings, are first fed successively from the feed magazine 19 to the face of the magnetic disc 17, and are then carried partially around said disc to the position where they are picked off the latter by engagement between the upper and lower guide bars 14 and 15 and the outer intermediate guide bar 20.

The piston rings are then pushed off of the edge of the magnetic disc by the following rings, and are moved along the guideway with their inner faces engaging the plastic guide plate 21. They continue their way past the demagnetizing unit 23, which operates to remove all of the magnetism in said rings before they are passed through the grinding zone between the grinding wheels 11, 11.

As a result of this demagnetizing process, deformations and warpage due to magnetic effects within the rings are effectively removed, so that the rings are ground in their normal, unmagnetized condition. This insures greater uniformity and precision in the final product, because the rings are ground in their normal shape, unaffected by magnetic deformation or warpage. In addition, it elimi nates any tendency for steel filings to adhere to the piston rings, or to accumulate by themselves in self-magnetized masses on the surfaces of the grinding wheels while the rings are being ground. Finally, the finished unmagnetized rings are easily handled for inspection, packing and shipping.

Although I have shown and described a certain embodiment of my invention, it will be understood that I do not Wish to be limited to the exact construction shown and described, but various changes and modifications may be made without departing from the spirit of the invenion as defined by the imprinted claims.

I claim:

1. in a feeding device for grinding machines, having opposed grinding wheels forming a grinding zone for work pieces, a workpiece magazine, a rotary magnetic disk for picking up workpieces successively from said magazine, guide means for picking 0ft workpieces from said disc and feeding them successively through the grinding zone of said grinding machine, and means independent of said magnetic disc for demagnetizing the workpieces, disposed immediately adjacent said guide means and between said disc and said grinding wheels.

2. The structure of claim 1 wherein the guide means includes a side plate made of non-inductive material along which the workpieces are slidable and the demagnetizing means consists of an electromagnetic core mounted adjacent said side plate normal to the latter in position to impose a demagnetizing flux on the workpieces as they pass along said guiding means.

3. The structure of claim 2 wherein the coil surrounds a laminated magnetic core, and said coil and core are enclosed in a casing secured on the outer side of the nonindnctive side plate.

References Cited in the file of this patent UNITED STATES PATENTS 1,548,562 Spencer Aug. 4, 1925 1,548,563 Spencer Aug. 4, 1925 1,628,618 Spencer May 10, 1927 2,657,504 Cadman Nov. 3, 1953 

